001/* ***** BEGIN LICENSE BLOCK *****
002 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
003 *
004 * The contents of this file are subject to the Mozilla Public License Version
005 * 1.1 (the "License"); you may not use this file except in compliance with
006 * the License. You may obtain a copy of the License at
007 * http://www.mozilla.org/MPL/
008 *
009 * Software distributed under the License is distributed on an "AS IS" basis,
010 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
011 * for the specific language governing rights and limitations under the
012 * License.
013 *
014 * The Original Code is part of dcm4che, an implementation of DICOM(TM) in
015 * Java(TM), hosted at https://github.com/gunterze/dcm4che.
016 *
017 * The Initial Developer of the Original Code is
018 * Agfa Healthcare.
019 * Portions created by the Initial Developer are Copyright (C) 2011
020 * the Initial Developer. All Rights Reserved.
021 *
022 * Contributor(s):
023 * See @authors listed below
024 *
025 * Alternatively, the contents of this file may be used under the terms of
026 * either the GNU General Public License Version 2 or later (the "GPL"), or
027 * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
028 * in which case the provisions of the GPL or the LGPL are applicable instead
029 * of those above. If you wish to allow use of your version of this file only
030 * under the terms of either the GPL or the LGPL, and not to allow others to
031 * use your version of this file under the terms of the MPL, indicate your
032 * decision by deleting the provisions above and replace them with the notice
033 * and other provisions required by the GPL or the LGPL. If you do not delete
034 * the provisions above, a recipient may use your version of this file under
035 * the terms of any one of the MPL, the GPL or the LGPL.
036 *
037 * ***** END LICENSE BLOCK ***** */
038package org.dcm4che3.image;
039
040import org.dcm4che3.data.Tag;
041import org.dcm4che3.data.Attributes;
042
043/**
044 * @author Gunter Zeilinger <gunterze@gmail.com>
045 *
046 */
047public class PixelAspectRatio {
048
049    public static float forImage(Attributes attrs) {
050        return forImage(attrs, Tag.PixelAspectRatio,
051            Tag.PixelSpacing,
052            Tag.ImagerPixelSpacing,
053            Tag.NominalScannedPixelSpacing);
054    }
055
056    public static float forPresentationState(Attributes attrs) {
057        return forImage(attrs, Tag.PresentationPixelAspectRatio,
058                Tag.PresentationPixelSpacing);
059    }
060
061    private static float forImage(Attributes attrs, int aspectRatioTag,
062            int... pixelSpacingTags) {
063        int[] ratio = attrs.getInts(aspectRatioTag);
064        if (ratio != null && ratio.length == 2
065                && ratio[0] > 0 && ratio[1] > 0)
066            return (float) ratio[0] / ratio[1];
067
068        for (int pixelSpacingTag : pixelSpacingTags) {
069            float[] spaces = attrs.getFloats(pixelSpacingTag);
070            if (spaces != null && spaces.length == 2
071                    && spaces[0] > 0 && spaces[1] > 0)
072                return spaces[0] / spaces[1];
073        }
074        return 1f;
075    }
076
077}